Time and temperature control for stokers



April 14, 1942; L. M. PERSONS TIME AND TEMPERATURE CONTROL FOR STOKERS Filed May 13, 1937 4 Sheets-Sheet 1 April 145, 1942. L. M. PERSONS 2,279,504

TIME AND TEMPERATURE CONTROL FQR STOKERS Filed may 13, 1937 4 Sheets-Sheet 2 flmflvroe: Lauren c: M Pzesomg;

A ril 14, 1942.

I TIME AND TEMPERATURE CONTROL FOR STOKERS L. M. PERSONS Filed May 13, 1937 4 Sheets-Sheet 3 Ann/Paves MPieso/lg April 14; 1942. M. PERSONS TIME AND TEMPERATURE CONTROL FOR STOKERS Filed May 15, 1937 4 Sheets-Sheet 4 //v I/E/VTOR: AAWRENcE M. PERsm/g Patented Apr, 14, 1942 TME AND TEMPERATURE CONTROL F STOKERS Lawrence M. Persons, St. Louis, Mo., a ssignor to Automatic Control Corporation, St. Louis, Mo., a corporation of Delaware Application May 13, 1937, Serial No. 142,401

7 Claims.

The present invention relates ,to a temperature system and suitable mechanism to effect its control. More specifically, the invention involves an adjustable space thermostat responsive to the temperatures of the space in which it is located, with a time control adjustment of its settings and an accessory control interoperated with it, together with a single electric clock mechanism outside the space thermostat casing for operat- 'ing both the time control and the accessory control.

In the mechanism there is a time relay to energize a furnace motor at given intervals. There is also a room thermostat switch responsive to changes in the temperature of the room, in circuit with the switch of the relay aforementioned that, closing upon existence of certain temperature. conditions in the room, operates the relay switch and energizes the furnace motor.

In systems of this nature where it has been desired to have time-controlled mechanism to alter the temperature of operation of the room thermostat during certain intervals, such as-at night, the room thermostat has been equipped with either spring or electric motor operated It is afurther object to provide responding mechanism in the room thermostat actuated by the remote clock and of such design as not to clockworks. Spring-actuated clocks have disadvantages that are well-known. Electric clocks, when used in close juxtaposition to thermostats, inevitably generate enough heat to influence the thermostat and to destroy its accuracy.

In the present invention both of these difllcultiesghave been overcome. The time relay in circuit with the furnace motor has an electric clock in it. Means are provided here in the nature of an electromagnet ratchet for operating the time mechanism of the room thermostat from this electric clock of the relay. The electromagnet in the room thermostat is caused to operate by a switch in the relay clock at given intervals relatively widely spaced. Consequently, the amount of heat generated within the room thermostat and casing is very small and is not enough to affect the thermostat. However, the mechanism is fully automatic and retains all the advantages of an electrical clock over a springactuated clock.

It is, therefore, an object of the invention to provide a fully automatic time mechanism for controlling a room thermostat, but of such design that it will not generate sufficient heat adversely to affect the thermostat.

More specifically it is an object of the invention to employ a remotely located electric time clock for actuating the time mechanism in the room thermostat.

generate sufficient heat adversely to affect the thermostat.

It is a further object to provide a room thermostat having time-controlled means for shifting its operating values, which time-controlled means'includes an electrical circuit adapted to beclosed by a preset mechanism and for a predetermined length of time, and automatically to be opened at the end of such period of time.

It is a further object of the invention to provide a thermostat, the operating values of which are adapted to be shifted by a rotatable member,

with aremote clock controlling a magnetic ratchet, which latter turns the rotating member, together with a switch periodically operatedby the .remote clock, for energizing the magnetic relay at given intervals.

It is a further object of the invention to provide a. switch operated by the clock for closing the circuit to the magnetic relay for only a very brief time interval.

It is a further object of the invention to provide a room thermostat having an anticipating heater thereon, together with means operated by the clock aforesaid periodically to close the circuit to a furnace motor and during such-periods of closing to energize said anticipating heater of said room thermostat, whereby to prevent closing of the room thermostat during such periodical operation of the furnace motor.

With these objects in view, together with such others as appear from the description to follow, reference is made to the drawings in which:

Fig. 1 is a front view of a room thermostat designed in accordance herewith;

Fig. 2 is a side elevation thereof;

Fig. 3 is a side elevation similar to Fig. 2 but with the casing removed; i

Fig. 4 is a front view withthe casing removed. some parts being broken away;

Fig. 5 is a side elevation with casing removed taken from the side opposite that shown in Fig. 3, and which-is the left side of Fig. 4;

Fig. 6 is a vertical section taken on the line 6-.6 of Fig. 4;

Fig. '7 is a vertical section looking forwardly taken on the line 'I-| of Fig. 6 and showing the magnetic ratchet mechanism;

Fig. 8 is a front elevation of the remote clock and relay used with the room thermostat of the previous figures;

Fig.9 is a section on the line 9-9 of Fig. 8;

, tions 24.

Fig. 10 is a view of the clock cam showing its operation on the two switches;

Fig. 11 is a sectional view looking at the front of Fig. 10 taken immediately below the clock cam;

Fig. 12 is a view from the backside of the clock cam;

Fig. 13 is an edge view thereof;

Fig. 14 is a section on the line |4|4 of Fig. 11;

Fig. 15 is a perspective view of the movable time switch bar;

Fig. 16 is a perspective view of the fixed switch bracket; and, I

Fig. 17 is a wiring diagram of the mechanism.

Reference will first be made to the room thermostat shown particularly in Figs. 1 to '1, inclusive. This room thermostat has a back member 23 to which its mechanism is attached and over which is secured a casing 2|. The front of the casing has a dial-receiving opening 22 therein and a graduated opening 23 about which are graduations 24.

Within the casing is a thermostat switch similar to that disclosed in my copending application Serial No. 79,052, filed May. 11, 1936. It includes a bracket 25 of S-shape secured to the back plate 23. An extension 23 projects vertically from the upper end of the bracket 25. A headed screw 21 (Fig. 6) is fixedly threaded into the extension 23. An arm 28 has secured thereto a sleeve 29 bearing about the shank of the screw 21. To this sleeve 29 is secured the inner convolution of a bimetal coil 33. A switch lever 3| is fastened to the outer convolution of this coil, projects downwardly, and has a contact point 32 and armature 33 its outer end.

An adjusting lever 35 is freely pivoted at 33 onto the arm 28. The lever 35 is tapered at one end 31, which end bears against a cam 38 fixed to a stud shaft 39 mounted upon the lower end of the S-shaped bracket 25. A convex spring element 43 is secured to one end of the shaft 38 and bears against the bracket 25 to urge the shaft inwardly. This spring 43 ofiers frictional resistance to rotation of the shaft whereby it will remain in set position. A handle 4| is secured to the other end of the shaft, the handle being attached to a disc 42 that has an arcuate projection 43 extending from its edge. The handle 4| is elongated and upstands from the disc 42. It acts as a pointer cooperating with the gradua- The arcuate extension 43 strikes a projection 43 turned up from the bracket 23 to limit the rotation of the handle 4| and'the cam 33.

A spring 43 islooped at one end into the lever 33 and at its other end into an insulating element 41 that, in turn, is secured to an upstanding flange 43 on a bracket 43 fixed to the back plate 23. At its upper end the lever 33 has an adjustable screw 33 threaded through opposed ears 3| and engageable against a movable cam 32, the functions of which will be described hereinafter. The spring 43. therefore maintains the lever 33 asfarto the leftinFig.4 asitis permitted togo by itscontact at one end with the cam 32 and at the other-end with the cam 33."

The contact 32 onthe movable switch blade 3| adjacent from it by a connecting portion 34. A screw 33 is threaded through the ear 33 and the clamp plate 33. It projecis beneath a spring plate 33 held beneath the two legs of the U-shaped switch plate 51. The spring plate 33 is secured by the rivets that hold the switch plate 31' in place. As will be explained hereinafter, the armature 33 on the switch blade 3| operates into and out of the magnetic field of the magnet iii. The extent to which the armature can move into this field is determined by the distance the relatively fixed contact 55 extends outwardly toward the contact 32. Since the distance the armature moves into the field determines the speed of the is adapted to cooperate with a relatively fixed contact 33. 33 of a U-shaped switch plate end 33 of which is secured to a clamp plate 33. Between the clamp plate "and a corresponding clamp plate 33 is held a horse-shoe magnet 3|, a screw 32 holding them together. The plate 33 is integral with an ear 33 parallel 31, the opposite The contact 33 is secured to one leg toitandspaeed'ls snap action produced by the magnet, adjustment of the screw 35 controlsthis snap, action, as will be apparent from the description to follow.

An electrical contact 33 is fastened to the back plate 23 and is in circuit with the connecting portion 34 to which is secured the clamping element 33. A spring element 39 is snapped in between the terminal 33 and the screw 35 so that this screw will be held in adjusted position. It may be held in adjusted position. It may be seen that this terminal 33 is, therefore, in circuit with the fixed contact 35.

Another terminal 13 extends through the back plate '23 and is in electrical communication with the s-shaped bracket 25. Thus, from the contact 13 the movable'switch blade 3| may be energize'd.

A third terminal 1| alongside the terminal 33 is in electrical circuit with the bracket 43. Between the bracket 49 and the pivoted arm 23 there extends an anticipating resistance heater element 12. Thus, if a circuit is established between the as. The shaft is drilled and tapped to receive a headed screw 13, this screw holding a convex spring 13 against the back plate 23, whereby to urge the shaft and its attached elements backwardly to resist movement and to hold the shaft in adjusted position. A handle element 33 is secured to a graduated disc 3| that in turn has an integral sleeve portion 32, as sleeve portion 32 fits over the outer end of the shaft 13. The cam proper 32, previously mentioned, comprises I a band wrapped around the; sleeve 32, and having one end upstanding'therefrom to act as the cam face. The handle may be adjusted about the shaft 131M secured in adjusted position by a. set screw. ,33. The graduations on the disc 3| register with a pointer 34 on thecasing 2|.

A ratchet wheel 33 is supported on the shaft 13 for rotation therewith. .To rotate the ratchet wheel, a plate, 33 is rotatably mounted on the shaft between the ratchet wheel 33 and a washer 31. AsisseeninFig.6, theshaft1l'ispeened over to hold the washer in place. 1

The plate 33 has an arcuate extension thereon, which extension has an upstanding flange.

seen in Fig. 3. The

back plate 20. An angular projection 95 extends alongside the coil and acts as an additional stop for the armature 88.

The bracket 95 has an opposite extension 91 extending to the side of the ratchet wheel opposite the magnet and having a tamed-down end upon which is situated a contact point 98. A movable switch blade 99 is attached to a fixed contact bracket I that has an upstanding flange to which the switch blade is attached. A terminal IOI leads from this bracket. The switch blade has at its free end a contact I02 cooperable with the fixed contact 98. inwardly therefrom and adjacent the ratchet wheel the switch blade has a pressed-out lug I03. This ing is adapted to be engaged by a lifting cam I04 fixed to the ratchet wheel 85. Thiscam I04 is normally so located that the switch is opened when the indicator is in starting position, as shownin Fi 1, at which time also the cam 52 is engaged beneath the screw 50 to shift the lever 35. It will be observed that upon energization of the magnet 94 the armature 88 is drawn upwardly until it strikes the magnetic core or the stop 95. This movement causes the dog 89 to drop back one tooth on the ratchet wheel 85. When the magnet is subsequently deenergized the spring 92 draws the plate downwardly and the ratchet dog advances the ratchet wheel the space of one tooth. The armature 88 has a projecting finger I extending through a slot I05 in the back plate 20. This finger limits the downward movement of theplate 85.

One end of the magnet coil is energized directly from the bracket 95 when the latter receives current through the closing of the con-' tacts I02 and 98. The other end of the magnet coil is connected with a lead I01 that terminates at the flange 41 of the bracket 49 and hence at the terminal 1 I.

The remote means periodically to energize the magnet 94 is shown in Flgs.8 to 16. This mechanism includes a plate M0 to the back of which isfastened an electric clock mechanism III of any suitable kind and which, through proper reduction gearing, rotates ashaft II2 once every hour. It will be observed that this'shaft projects through the plate IIO. This rotating shaft has means to close at given intervals two switches that control certain circuits. On the plate IIO are terminals H3 and M4 to receive the line power. As shown in the wiring diagram of Fig. 1'1, the line current leads directly to a primary II5 of a transformer. In parallel with this primary is the clock motor I I5 which,.therefore, will run at all times that the line current is connected to-the two terminals 3' and II4.' Two terminals H1 and H8 are also provided for the leads from a-furnace motor II9. This may be the stoker motor of a coal furnace or any similar piece of electrical equipment that may be energized to cause the particular type of furnace used to give of! more heat. There is also provided a main switch I20 of the type. described in my copending application Serial No. 88,714, filed July 3, 1936, now Patent 2,207,942, issued July 15, 1940. This switch I20has two contacts I2I and I22 adapted to be brought together. The contact I22 is connected to the terminal II8 by a lead I23. The fixed terminal I2I is connected with the terminal II3 through one of the clock leads by a lead I24. It may be seen that the furnace motor 'v-notches I54 and I55.

' cam. If, however,

is, therefore, connected across the terminals 3 and H4 through the switch I20 and will be energized whenever the switch I20 is closed.

As has been described in my copending application referred to, the switch I20 is of the ther-- mal relay typeactuated by a heater I25. When this heater is energized the switch I20 is closed.

. The transformer has a secondary I25, one lead from which extends to a terminal I21. The opposite lead of the transformer extends to a point I28, from which point branches the heater I25, the other end of which is connected to a terminal I29. The second lead from the branch point I28 is a line I30 extending to a fixed con tact I3I of a switch I32,.the details of which will be given hereinafter. The movable contact I33 of this switch is connected to a lead I34 extending to a terminal I35.

'From the terminal I29 there also extends a lead I35 to a fixed contact I31 of a switch I38, to be described in detail. This switch includes a movable contact I39 to which is connected a lead I40 extending to a terminal I.

The two switches I32 and I38 are operated at given intervals by the clock mechanism I II. The switch I32 will now be described.

Mounted upon the time shaft II2 are cam discs I and I45. The disc I45 has integrally formed therewith oppositely extending collars I41 and I48. Through the collar I41 extend set screws I49 adapted to hold the cam discs against rotation relative to the shaft H2. The disc I45 fits about the collar I48 for .rotation relative to the disc I45. A screw I50 fits through an arcuate slot I5I in the disc I45 and is threaded into the disc I45. Thus, the two cam. discs have limited rotary adjustment one relative to the other, as'

defined by the length of the slot I5I. The disc I45 has two opposite V-shaped notches I52 and I53- The disc I45 has identical oppositely spaced Additionally, the disc I45 has the notch I55 and the disc I45 has the notch I51. Consequently, with the two discs in the relative positions shown in Fig. 12, the notches I52 and I54, and I55 and I53, -coincide.

There will then be two opposing notches on the the disc I45 be rotated relative to the disc I45 until the screw I50 engages the opposite end of its slot; the notch I55 will coincide with the notch I51, but all of the other Con-- sequently, there will be only one notch presented per revolution. Hence, by shifting the relative positions of the discs I45 and I45 the cam element may be made to present either one or two. equally spaced V-notches per revolution.

The switch I38 includes the relatively fixed contact I31 and the relatively movable contact I39. Both of thesecontacts are fixed to a bracket .I50 that has a flange I5I extending down parallel with the switch blades. As described in my copending application referred to, a screw I62 having a head engageable with a blade I83 of the fixed contact is threaded into a collar on the flange I5I. An adjusting wheel I54 is fastened to the screw for rotation therewith. The screw I82 passes through an opening in a blade I55 holding the movable contact, so as not to touch the same. By this means rotation of the wheel I54 causes the fixed contact I31 to be adjusted toward or away from the movable contact I38.

The blade I55 has a turned-down end I88 thereon that constitutes a follower engageable with the cam discs. The inherent resiliency of the spring blade maintains this follower in conspaced pins m ill will draw the bar Ill back position 'of Fig. 8, again opening the contact."

As shown in Fig. 10, is on an arcuate part is maintained open.

however, a notch is presented to the folthe period is apt movebefore the switch is closed is determined by the position of the adjusting wheel Ill. Since the notch is V-shaped, this adjustment likewise determines the length of the period of time during which the switch is closed. Such is described in my copending application referred to.

The disc Ill is provided with a extending from its inner face and arranged circularly. The switch I32 is provided witha movable contact I33 somewhat extenuated. This contact is formed on a bar I'll. This bar is subject to a combined pivotal and translatory movement. It is mounted over a second bar III' rigidly secured to the plate I Il. The bar III has an upstanding flange I12 to which is secured the relatively fixed switch blad'e' I'll, there being insulation IIl preventing electrical contact between them. The contact I3I is mounted on this blade Ill. The bar I'll likewise has a flange Ill having an open ended slot I'll into which the end III of the first bar IIll is adapted to fit and by which the same is guided. The bar I" is provided with a slot Ill engageable around a collar. I'Il secured to the second bar I'II by a screw Ill. The arm I'll may thus pivot about the screw Ill and also may reciprocate relative thereto within the limits ermitted by the slot III. A coil spring IlI fixed to the plate Ill at one end and to the bar Ill at its other end urges the bar toward the closed end of the slot I'll with a relatively light force. It likewise urges the bar I'll downwardly as far as possible likewise with a relatively light force.

The bar I" has medially thereof a projection Ill. This projection has a lower shoulder Ill and an upper shoulder I" connected by a sloping edge Ill. The two shoulders Ill and I 81 are spaced apart by slightly less than the linear distance between successive pins Ill. In the position of Fig. 8 the first bar I'll is in its innermost position wherein the projection Ill is located between two such pins Ill. As the cam disc Ill rotates clockwise, a pin Ill will engage against the shoulder Ill, lifting the bar Ill substantially vertically. In this movement the contacts I33 and III are separate. When, however, after suitable rotating movement, the pin Ill begins to remove itself from the shoulder Ill, it will slide under the sloping face Ill. The spring IlI, aided by gravity, will .then draw the bar I'll downwardly while maintaining in Fig. 8, as far as possible. however, displaces the lower end of the bar to the left, causing the contact ill to wipe over the contact Ill, as illustrated in Fig. 10. When the bar travels sufiiciently far so that the shoulder I" can drop beneath the pin Ill, the spring to the starting Thus, it may be seen that the contacts of the switch I32 are closed only for a very short period of time. In accordance with the number of pins shown, the switch I32 will, close six times during the hour and the duration of each closing period may bewin the neighborhood of onetwentieth of a second. It is desirable that the switch be mounted so that the rod I" will fall pa a y. y srav ty d Pa ti y by sprins series of equally it to the right, The sloping face,

tached.

tion. If it operates solely by gravity, the contacts are apt to be closed for too long a period; whereas, if spring action is relied entirely upon, to be too short.

Thus, it may be seen that the clock mechanism III closes the switch I32 six times during an hour and closes the switch I38 one or two times during the hour. Of course, it will be understood that the number of rotations of the shaft I I2 per hour may be varied, as may the number of pins used, or the design of slots.

In connecting the two mechanisms described together the terminal 68 is connected to the terminal I29 by the line Ill. The terminal I0 is connected with the terminal I by the line Ill. The terminal II is connected to the terminal I21 by the line I92; and the terminal Ill is connected to the terminal I35 by the line Ill.

The operation of the mechanism is as follows:

The operation of the room thermostat switch by the bi-metal coil 30 is as follows:

As the ambient-temperature cools the bimetal, the switch blade 3I will be moved to the right in Fig. 4 (left in Fig. 17) until the contact 32 thereon meets the fixed contact 55. Needless to say,

the snap-action mechanism hastens the last part' of this movement.- The preliminary or starting position of the switch blade 3I for anyparticular temperature is determined by the'position of the inner convolution of the bimetal coil 30 and hence by the relative angular position of the arm 28 to which this inner convolution is atature is sufiicient to close the switch from the position of Fig. 4, and if the arm 28 be pivoted in a counterclockwise direction, the contact 32 will be moved initially closer to the contact ll so that a drop in temperature of some lesser amount such as 2 will become sufllcient to close the switch.

So the position of the arm 28 controls the temperature at which the switch will close. The position of this arm, in turn, is controlled by the position of the lever 35. The lever 35 is shifted by two independent means. The first is the cam ll operated by the handle ll. As this cam is rotated clockwise from the position in the drawings to some position such as 75, the lower'end of the lever 35 will be moved outwardly while the upper end acts as a pivot Suchmovement of the lever 3l produces a counterclockwise shifting of the arm -2l. Hence, the initial position of the switch blade 3| is shifted closer to the contact 55. If it be assumed that the ambient temperature is 78, for the position shown in the drawings, a drop of 8 would be necessary to close the switch; but, if the handle ll be moved as suggested, a drop of 3 would be sufilcient to close the switch.

The time mechanism operates as follows:

In the position shown the thermostat is set for its higher operating value, which may be referred to as the daytime value. When it is desired to have the furnace operate at a lower value isters with the index 84. Thus, if the time is 11:00 o'clock p. m. and it is desired to have the furnace come back to daytime value at 6:00 a. m., the handle ll will be turned until numeral 7 of the dial registers with the index ll, since If, for instance, a drop of 5 in temper- 1 for such motion.

-of the magnet, the spring 82 from 11:00 oclock p. m. until 6:00 a. m. is seven hours.

As soon as the handle is withdrawn from beneath the screw 58. pennits the lever 35 to move to the left under the influence of the spring 48, it pivoting about turned, the cam 52 is the contact of its lower end with the cam 88.

cause the dog 88 to be moved backwardly the deenergization space of one tooth. Then, upon draws the armature down and the dog 88 advances the ratchet wheel this distance of one tooth until the armature is stoppedby engagement of the finger I88 with the lower end of the slot I88. In the upward movement of the armature, the ratchet wheel is prevented from following because of the friction produced by the spring I85 acting against the back of the plate 28.

The energization of the magnet 84 is controlled by the switch blade 88. In the position of Figs. 4 and 7 the contacts I82 and 88 are,parted by action of the cam I84 on the switch blade. As soon, however, as the handle 88 is turned, the cam I84 is withdrawn and the switch closes, permitting the magnet to be energized.

The'ratchet wheel will be thus turned one tooth at a time for a given length of time until the handle 88 is brought back up to registration with the index 84. Shortly prior to this time, perhaps beginning two hours before the time occurs, the gradual slope of the cam will begin to move the screw 58 gradually to raise the position of operation of the thermostat. When the handle is in the vertical position, the cam 82 will be fully under the screw 88. At the same time the cam I84 will come under the pressure lug I88 to open the switch contacts I82 and 88 to prevent further energization of the magnet this position until further manual adjustment is given to it, either by shifting of the handle 88, i

or shifting of the handle 88.

The gradual slope of the cam 52 acting over -a substantial period of time prevents overriding the screw 58.

The action of the magnet 8I on the armature 88, in addition to the snap-action effect, gives the switch a differential." In other words, the value or temperature at which the switch closes is slightly different from that at which it opens. This is susceptible of adjustment by the screw 88, as will be understood. 1

In connection with this differential mechanism, the anticipating heater I2 is employed. If it be assumed that the differential is 3, this anticipating heater will be designed to produce a heat equal to slightlyless than this differential. The heater is caused to operate whenever the thermostat switch is closed, since an inspection of the wiring diagram shows that the heater is in series with the thermostat switch.

It, therefore, the switch is designed to oper i at time mechanism could be employed, but only at The thermostat, therefore, will remain in I I88 is closed, the anticipating heater is energised.

Should the room at this time 70 so that the room thermostat is on the verge of closing, heating hour and then for just 73 but not to close until the temperature drops to 70, the anticipating heater may produce a quantity of heat equal to a change in ambient temperature of 1 /2. Therefore, when the switch closes upon drop of temperature to 70, the anticipating-heater will come on. As the temperature rises to 71 2 which it will do over a period of time, the switch will be opened in advance of its normal differential setting of 73. But, since theheating plant requires a certain period'of time before it settles down after its cut-off, it will continue'toproduce heat. The provision of the anticipating heater, therefore, takes off of this characteristic of'heating plants and cuts of! the active operation of the plant sufficiently in advance so that the heat produced after the cutoff is just the properamount to bring the room up to its proper temperature of '73". Once the switch opens, 'however, the temperature must drop the full differential value to '10 before the switch again closes. It is, of course, obvious that the value of this resistance here will depend upon the particular system being used.

If the magnet 84 is energized only six times an a fraction of a second, the amount of heat generated within the thermostat casing is so small that it has no adverse effect uponthe bimetal. Furthermore, this magnet structure requires little space so that the room thermostat can be made small and compact.

The present system, while,attaining the above desirable characteristics, does so without increasing the mechanism necessary, since it employs the use of a time mechanism already in the system for periodicallyenergizlng the magnet 84. Of course, it will be understood that additional the sacrifice of economy.

The energizingmear'is consisting of the struc-, ture mounted upon the plate II8 operates as follows:

The cam discs I and I48, being duly adjusted to give the proper number of notches, are rotated by-the clock motor I I8. of course, is merely any constant speed motor. If the disc I45 rotates one revolution an hour, the switch I82 will close six times an hour. This switch isput in series with the magnet 84 through the switch blade 88. The fore, would be given seventy-two teeth.

As will be understood, the switch I88 closes once or twice per hour. The operating heater I28 is in series with this switch I88 so that. when the switch closes, the heater,I28 energizes and, acting upon the bimetal of the switch I28, closes the contacts I 2I and I22 to put thefurnace motor into circuit. I

It is desirable to have rendered inoperative when the time the room thermostat relay switch m is closed. Since a certain period of time is necessary before the effects of turning on the furnace are felt upon time relay might cause operation of the furnace motor; but, before the roomcould heat, the room thermostat might close. This is prevented by connecting the anticipating heater 12 in series with the switch I88. Hence, whenever the switch be cooling down to of the heater 12 produces a temperature at the bimeta'l 88 of Il which is suiflcient to prevent closing of. the switch. The amount of heat providedby the periodic automatic refueling of the furnace will take effect in This motor 8,-

ratchet wheel 88, there- I the room thermostat, the

whereupon the heater I25 shaft 2 closes the switch contact In, line I,

through the the ratchet wheel II is tion, the cam Ill the room before the thermostat ll will have again cooled down to 70 after the switch I3! is opened by the clock mechanism.

Fig. 1'7, discloses how the above takes place. With power connected to the terminals H3 and Ill, the primary II5 of the transformer and the clock motor IIi are immediately energized, they being in parallel across the terminals. With the switch I open, the furnace motor II! will re;- main oil. Shouldthe room thermostat 30 cool to close the contacts 32 and 55, circuit will be established as follows, beginning with the terminal I21 of the secondary I26: From terminal I21 of the secondary I26 through line I92 to terminal II of the thermostat; thence through anticipating heater I2 to terminal it, through the bimetai II to contact 82, contact BI, terminal 6|, line m, terminal In, relay heater m, branch I28, and back into the secondary I28. Energization of the heater I", acting upon the bimetal of the switch I 2., and puts the furnace motor across the terminals III and II. The furnace motor, therefore, will produce heat that ultimately will raise the temperature in the room to 'a value which, coupled with the temperature produced by the anticipating heater I2, will open contacts will be deenergized. The furnace being hot, however, the temperature in the room will continue to rise. until it reaches the value equal to the opening alue of the thermostat, plus the value of the an icipating heater. It will not. however, override this value, since the heater I2 is designed to be Just enough to balance the surplus heat of the furnace at the time of cut-oi! and prevent such overriding.

When the clock motor II operating on the III, circuit from the secondary I26 is as follows: Terminal I21, line I92, terminal II, anticipating heater I2, terminal II, line Ill, terminal Ill, line I, contact I, terminal I29, heater I 25,

branch I28, and back into secondary I28. As

before, energizing of the heater I cuts the furnace motor II in circuit. The anticipating heater I2 will prevent closing of the room thermostat.

After the handle II has been rotated, the clock motor periodically will close the switch I32 to energize the magnet 94 so long as the contacts 90 and I 02 are closed. If it be assumed that the latter contactsare closed. at the time that the switch I32 closes, circuit is asi'ollows: From the terminal I21 by line magnet ,contact 98, contact I", to the terminal III, line Ill, terminal I", line I", contact I, contact III, line I, branch I", and backinto the secondary I2. cuitwillbeseentobeinparallelwiththerelay heater I2. and is entirely dependent upon the position of the switch contact "2, as determined by the position of the ratchet wheel,' Assoon as returned to starting posiwill open the contacts II and I02 to take the magnet 9! out. of circuit, and thereby to stop further movement of the wheel.

It will-be seen from the foregoing that a mechanism has been provided that will attain the ob- Jectives set forth.

What is claimed is:

1. In a mechanism of the kind described, a thermal switch, and mechanism mechanically to shift the switch independently of the temperature, said mechanism including a cam, means to rotate the cam, said closes the contacts III an I22 32 and II,.

I" to the terminal 1|,

' switch operated wheel and a ratchet dog to rotate .the same, an

electromagnet to shift "the ratchet dog wherebyv thermal switch and means mechanically to shift the switch independently of the temperature, said means including a shaft, manual means to rotate the shaft a predetermined distance around from a starting position, a first cam operated by the shaft and means operated by the cam to shift the switch, a second-cam operated by the shaft, an electro-magnetically-operated ratchet adapted to shift the shaft, a circuit for the electromagnet, a switch in said circuit, said second cam maintaining said switch open when the shaft is in starting position, so that upon advance of the shaft the electromagnet switch will be closed until the shaft is returned to starting position, and then will be opened.

3. A control mechanism for temperature-influencing devices, including a main switch in circuit with the temperature-influencingdevice, electrical means to operate the main switch, a thermal switch in circuit with said electrical means, a clockworks, a first switch operated by said clockworks, a circuit including said first clockworks switch and said electrical means, whereby when the first clockworks switch is closed the temperattire-influencing means will be put in circuit, means also put in circuit upon closing of the first clockworks switch to retard operation of the thermal switch, means to shift'the temperature of operation of the thermal switch including an electrical-device, a circuit therefor, and a second by said clockworks to controlthe circuit through the electrical device.

4. In combination, a furnace mechanism, a control circuit for said furnace eluding a main switch, electrical means to close the main switch, a room thermostat, a circuit through said thermostat and said electrical means to close the main switch when the room temperature drops to a predetermined value and cause said furnace mechanism to produce additional heat, electrically-operated means to shift the room thermostat to alter its operating value including a rotatable member movabl a given angular distance from starting position and electric mechanism to return it to starting position, a camon said rotatable member, an element by the cam when the same is in starting position to move the thermostat, clockworks, a flrst switch operated by the clockworks, ;a, circuit through said first switch and said electrical means to close the main switch at given time intervals, by the clockworks, a circuit through said second I switch 'and'said electrical mechanism means to means including a ratchet shift the room thermostat, whereby said shifting mean is operated from the clockworks, and,

means in circuit to retard closing operation of the cuitthrough the first clockworks. switch.

5. In combination, an electrically-operated furnace mechanism, a circuit therefor, a main switch in the circuit, an electrical clockworks, a room thermostat switch operable to close the with the first clockworks switch mechanism ina'second switch operated of the room thermostat during furnace mechanism by the cir- I the clockworks to cause energization of said moving means, and means automatically to cause deenergization of said moving means after mined period of movement of said member.

6.In combination, an electrically-operated heat change mechanism, a circuit therefor, a main switch in the circuit, a room thermostat switch closable to cause said main switch to close, an anticipating heater in circuitwith the room thermostat to be energized upon closing thereof and to produce a biasing heat acting upon said thermostat to produce a tendency in the same toward opening position, clockworks, a circuit controlled by the clockworks to cause the main switch to close at given intervals, said circuit also including said anticipating heater whereby the room thermostat will be retarded from closing during and after operation of the heat change mechanism by the clockworks.

'7. In combination, a furnace, a first control circuit for said mechanism including a main switch; electrical means to close the main switch;

a clockworks, two switches operated by the clockworks; an adjustable room thermostat, the room thermostat being entirely separated from the clockworksj a second circuit through said electrical means on the main switch and room thermostat to close the main switch upon shifting of the room thermostat in response to changes in temperature, whereby to operate the furnace a deterposition,

spring for returning the same, a

rotatable member, an element adapted to be mechanism; manual means to adjust the room thermostat to vary the temperature or operation, separate electrically operated means to alter the temperature of operation from its normal value including a rotatable member movable a, given angular distance from starting position and a dog and ratchet to return it to starting positio with an electromagnet for moving the dogand a first cam on said shifted by the cam when the rotatable member is in starting position to shift the thermostat; a third circuit through the first clockworks switch and the electrical means to close the main switch, said switch and circuit being closed by the clockworks at given intervals; a fourth circuit through the second clockworks switch and said electroniagnet, said second switch being closed periodically for instantaneous intervals whereby said magnet may shift the rotatable member; a second cam on the rotatable member and a switch adapted to be opened thereby when said member reaches starting position, said switch being in the fourth circuit whereby to stop rotation of the angular member upon its return to initial at which position the first cam on the rotatable member has returned the room thermostat to its normal operating value.

LAWRENCE M. PERSONS. 

